Rotary and swivel couplers are frequently utilized to connect fluid conduits together. These rotating devices are especially useful when connecting a fluid conduit to a rotating or pivoting device. The swivel coupling, which may rotate about the axis of the input fluid conduit or alternatively, may rotate about a perpendicular axis, is especially useful where maneuverability is essential to the satisfactory operation of the device.
Typically, these swivel couplings consist of a swivel body having an internal cavity. An internal fluid passageway interconnects the cavity with a port which is adapted for interconnection with a fluid conduit. A tubular rotating member is engaged within the cavity. A second fluid passageway, which passes through the rotating member, interconnects the first fluid passageway and a second port for connection with a second fluid conduit. A bearing is disposed between the rotating member and the cavity to allow for the rotation of the rotating member. The assembly may include a seal to prevent passage of fluid from between the rotating member and the cavity and means for preventing the axial movement of the rotating member from within the cavity.
While prior art swivel couplings are quite satisfactory in most instances, they have several disadvantages. For example, prior art swivel couplings are typically made from metal components. While metal components provide a coupling with high strength, relatively wear-resistant components and the ability to retain high pressures while maintaining tight tolerances, metal components can be a source of chemical contamination. This contamination can be through ionic, catalytic, or through direct chemical reaction. Metal can also conduct electricity and electrical discharge and when placed in contact with the flow, can contaminate certain fluids.
Recent technological advances have increased the need for fluid swivel coupling devices that provide free rotation without the use of metal components which could contaminate the fluid. For example, in the semiconductor industry, rotary tables are commonly used for lapping or cleaning semi-conductor wafers. A fluid swivel coupling facilitates the fluid conduit feed into the rotary table. However, because metal components in the fluid flow path can potentially contaminate the passing fluid, there is a need for a fluid swivel coupling device which has no metal components along the fluid flow path.
Modern swivel coupling applications, including delivering fluids for lapping semiconductor wafers, often require the passage of abrasive fluids and slurries. These abrasive fluids can significantly wear against seals and tightly toleranced interfacing parts along the flow path. Typically, metal components are used to resist this wear. However, the use of metallic components along the flow path may not be an option clue to concerns regarding fluid contamination and corrosion. Thus, there is a need for a fluid swivel coupling device which does not use metal components along the flow path and which is capable of resisting wear due to the passage of abrasive fluids.